Efficient top-k algorithms for approximate substring matching

There is a wide range of applications that require to query a large database of texts to search for similar strings or substrings. Traditional approximate substring matching requests a user to specify a similarity threshold. Without top-k approximate substring matching, users have to try repeatedly different maximum distance threshold values when the proper threshold is unknown in advance. In our paper, we first propose the efficient algorithms for finding the top-k approximate substring matches with a given query string in a set of data strings. To reduce the number of expensive distance computations, the proposed algorithms utilize our novel filtering techniques which take advantages of q-grams and inverted q-gram indexes available. We conduct extensive experiments with real-life data sets. Our experimental results confirm the effectiveness and scalability of our proposed algorithms.